In the prior art, in order to increase a peak rate of a user equipment (User Equipment, abbreviated as UE), a concept of carrier aggregation (Carrier Aggregation, abbreviated as CA) is introduced in a further evolution (LTE-Advanced, abbreviated as LTE-A) of the technology of long term evolution (Long Term Evolution, abbreviated as LTE), when the UE needs to aggregate data transmitted by multiple carriers, an evolved base station (evolved Node B, abbreviated as eNB) may allocate multiple serving cells or component carriers (Component Carrier, abbreviated as CC) for the UE, where each CC may correspond to one serving cell. Specifically, a CC may act as a primary CC (Primary CC, abbreviated as PCC), and a cell where the PCC is located may be called a primary cell (Primary Cell, abbreviated as PCell). Other CCs may act as secondary CCs (Secondary CC, abbreviated as SCC), and cells where the SCCs are located may be called secondary cells (Secondary Cell, abbreviated as SCell). Generally, when the UE applies carrier aggregation, in order not to excessively increase times of UE's blind detection on a physical downlink control channel (Physical Downlink Control Channel, abbreviated as PDCCH), on the PCell, blind detection needs to be performed on PDCCH scheduling information of a common search space (Common Search Space, abbreviated as CSS) and a dedicated search space (Dedicated Search Space, abbreviated as DSS), while on the SCells, blind detection only needs to be performed on the PDCCH scheduling information of the CSS. Regarding messages such as paging messages and broadcasting messages that need to be sent through PDCCH scheduling in the SCells, the UE cannot obtain the messages from the CSSs of its own SCells, but instead, obtains the messages by using a dedicated radio link control (Radio Link Control, abbreviated as RLC) message.
The inventor finds that the prior art at least has the following problem: when the UE performs a contention-based random access channel (Random Access Channel, abbreviated as RACH) on the SCells, if all RACH procedures are implemented on the SCells, the UE needs to monitor the CSSs of the SCells to obtain scheduling information of random access response messages of the SCells, thereby inevitably increasing times of blind detection and a false alarm probability.